This application is based on Japanese Patent Applications Nos. 2001-118743, 2001-118745, and 2001-118746, the contents of which are incorporated herein by reference.
The present invention relates to a head jetting property maintenance device for maintaining an ink jetting property of a recording head for jetting ink droplets to a recording medium inconstant performance and a recording apparatus with the head jetting property maintenance device.
Generally, an ink jet printer as one form of the recording apparatus is constructed with a printing head mounted on a carriage, which reciprocates in the main scan direction, and a recording medium feeding device for intermittently feeding the recording medium, such as a printing sheet of paper, step by step at a predetermined amount in the sub-scan direction. In operation, the printer moves the printing head in the main scan direction while feeding the recording medium in the sub-scan direction. At the same time, the printer jets ink droplets from the printing head to the recording medium.
Normally, in the mono-color ink jet printer, one printing head is mounted on the carriage. As for the full color ink jet printers, some are provided with a black printing head for jetting black ink and a plurality of color printing heads for jetting color inks of necessary colors, such as yellow, cyan, and magenta, mounted on the carriage, and the others are provided with one printing head capable of jetting color inks of necessary colors, such as black, yellow, cyan and magenta, mounted on the carriage.
The printing head of the ink jet printer thus constructed includes pressure generating chambers and nozzle orifices communicating to the pressure generating chambers. By pressurizing the pressure generating chamber where ink is stored at a predetermined pressure, an ink droplet of controlled size is jetted to the recording medium from the nozzle orifice associated with the pressurized chamber. Accordingly, when the ink jetting property of the printing head at the nozzle orifice varies, the property variation greatly affects the quality of the recorded or printed image. To avoid this, it is essential to maintain the ink jetting property in constant performance.
The ink jetting property is varied by various causes: viscosity increase of ink due to evaporation and drying of the ink component at the nozzle orifices, clogging of the nozzle orifices by solid matters, dust sticking, air bubble entering, and others. To cope with this, the ink jet printer is equipped with a head jetting property maintenance device which removes the factors for causing the property variation to maintain the ink jetting property in constant performance.
The head jetting property maintenance device includes a capping device, a suction pump and a wiping device. The capping device is configured so as to seal the nozzle forming surface of the printing head in a non-print mode of the printer to isolate the nozzle orifices from outside. The capping device has functions to suppress the evaporation and drying of the ink and thus to suppress the viscosity increase and solidification of the ink. While the nozzle forming surface is sealed with the capping device, it is impossible to completely prevent the clogging of the nozzle orifices by solid materials and the entering of air bubbles into the ink passage. Accordingly, to completely remove the clogging and bubble entering problems, the suction pump is provided.
The suction pump applies a negative pressure to the nozzle orifices in a state that the capping device seals the nozzle forming surface. Under the negative pressure applied, ink is forcibly discharged from the nozzle orifices thereby removing solid materials and air bubbles. Usually, the operation of forcibly sucking and discharging the ink by the suction pump is carried out when the ink jet printer is stopped for a long time and is operated again, and when the user finds the quality deterioration of the printed image, and operates a dedicated switch on the operation panel.
When the discharging operation by forcible suction of the suction pump is carried out, ink often sticks to the nozzle forming surface of the print head, and the turbulence of the meniscus often occurs. Further, foreign materials tend to stick to the nozzle forming surface of the printing head with time. To remove the foreign materials, the wiping device is provided to wipe the nozzle forming surface according to the necessity.
The wiping device includes a wiping member which is formed with an elastic plate made of rubber or the like, and is clamped at the base end with a holder. The wiping device is configured so that the edge part of the top end of the wiping member is elastically pressed against and reciprocatively moved on the nozzle forming surface, thereby cleaning the nozzle forming surface. The wiping device has a function to regulate the meniscuses of ink at the nozzle orifices, viz., to stabilize the same, in addition to the function of wiping off the ink and the foreign materials sticking to the nozzle forming surface.
In a conventional head jetting property maintenance device, as described in Japanese patent Publication No. JP-A-11-138830, the driving of the capping device and the wiping device is switched to and from the driving of the suction pump depending on the rotational direction of a motor as a drive source, by use of one planet gear.
FIG. 80 is a side view showing another conventional head jetting property maintenance device. As illustrated by (a) of the figure, in the head jetting property maintenance device, the capping device 1 and the wiping device 2 are mounted on a supporting part 3 which is rotatable and vertically movable, while being disposed angularly spaced by 90xc2x0. A partially toothless gear 4 is fastened to the supporting part 3, and the supporting part 3 is disposed such that the partially toothless gear 4 comes in contact with the partially toothless cam 5. The head jetting property maintenance device is provided with a suction pump (not shown).
With such a construction, in a non-print mode of the printer, to seal the nozzle forming surface of the printing head and to isolate it from outside, the head jetting property maintenance device, as shown in (a) of the figure, is set such that the supporting part 3 is positioned at the top part in a state that the capping device 1 is directed upward, by means of the partially toothless cam 5.
When the nozzle forming surface is wiped after the printing in a manner that the edge part of the top end of the wiping member is elastically pressed against the nozzle forming surface and reciprocatively moved thereon, the partially toothless cam 5 is turned to bring the teeth 5a of the partially toothless cam 5 into engagement with the teeth 4a, and turns the supporting part 3 together with the partially toothless gear 4. Finally, as shown in (c) of the figure, the supporting part 3 is set such that the supporting part 3 is positioned at the lower-most part in a state that the wiping device 2 is directed upward, by means of the partially toothless cam 5.
In the former related art, the vertical movement of the cap and the reciprocal movement of the wiper are performed based on the unidirectional rotation of the motor. Accordingly, it is impossible to initialize the positions of the cap and the wiper. For this reason, it is necessary that flags to detect the initializing positions of the cap and wiper are provided on cams for driving the cap and the wiper thereby effecting sensing them. Accordingly, the sensors are essentially needed, and the assembling and adjustment of the device are complicated. The cost to manufacture the device is increased.
Further, the pump is also driven to turn in only one direction. Therefore, particularly when the tube pump is used, it is impossible to release the pulley from the tube. There is a fear that the pulley is left pressing the tube. To avoid this, it is necessary to move the carriage and lock the planet gear, and then to release the pulley. Accordingly, a mechanism which leaves the printing head capped even when the carriage is moved is needed. As a result, the assembling and adjustment of the device are complicated, the cost to manufacture the device is increased, and the device size becomes large.
The above conventional head jetting property maintenance device may be constructed in a simple mechanism, and hence is useful. In a state that the capping device 1 or the wiping device 2 is in a setting state, viz., the supporting part 3 is positioned at the upper-most or lower-most part, the teeth 5a of the partially toothless cam 5 is not in mesh with the teeth 4a of the partially toothless gear 4. The supporting part 3 is in a free state.
Additionally, as the head jetting property maintenance device must be rotated as a whole, a broad space is needed therearound. This leads to size increase of the ink jet printer into which the printing head is incorporated. Further, the position accuracy of the capping device 1 and the printing head is apt to be deteriorated possibly causing imperfect capping.
In a state that the capping device 1 or the wiping device 2 is in a setting state, viz., the supporting part 3 is positioned at the upper-most part or the lower-most part, the teeth 5a of the partially toothless cam 5 is not in mesh with the teeth 4a of the partially toothless gear 4. And the supporting part 3 is in a free state.
Accordingly, there is a chance that the user touches the supporting part 3 to turn the supporting part 3. In that case, it could be difficult to return the capping device 1 or the wiping device 2 to a predetermined position. The tips of the teeth could collide with each other and be possibly broken, when the teeth 5a of the partially toothless cam 5 fits together with the teeth 4a of the partially toothless gear 4. Furthermore, in assembling the head jetting property maintenance device, an exact phase adjustment between the partially toothless cam 5 and the partially toothless gear 4 is required, and this phase adjustment work is troublesome work.
Accordingly, an object of the present invention is to provide a head jetting property maintenance device which is capable of always stably performing the capping, wiping and the pump driving operations with a simple construction, and a recording apparatus provided with the head jetting property maintenance device.
1) To accomplish the above object, there is provided a head jetting property maintenance device for maintaining an ink jetting property of a recording head for jetting ink droplets to a recording medium, the head jetting property maintenance device comprising: a wiping device for wiping the recording head; a capping device for sealing the recording head; and a driving device including two planet gears for transmitting a drive force to the wiping device and the capping device and a rotary device for rotating the planet gears, wherein the driving device is able to drive the wiping device and the capping device in either of normal and reverse directions of the rotary device by switching an engagement of one of the planet gears to an engagement of the other of the planet gears.
2) In the head jetting property maintenance device 1) above, the driving device includes a sun gear being coupled to the rotary device and in mesh with the planet gears, and a partially toothless gear being coupled to the wiping device and the capping device and in mesh with the planet gears, and the driving device is disconnected from the wiping device and the capping device after driving the wiping device and the capping device.
In the head jetting property maintenance device thus characteristically featured, the cap of the capping device and the wiper of the wiping device are moved bidirectionally, viz., forwardly and reversely. Accordingly, the positions of the cap and wiper may be initialized easily. Therefore, in the invention, unlike the conventional device, there is no need to provide flags to detect the initializing positions of the cap and wiper provided on cams for driving the cap to effect sensing them. Accordingly, the assembling and adjustment of the device are simplified, and the cost to manufacture the device is decreased. Further, the cap and the wiper are reliably set at predetermined positions by merely rotating the partially toothless gear to a partially toothless part by a predetermined angle.
3) The head jetting property maintenance device 1) or 2) may further comprise a suction device for sucking a space within a cap of the capping device sealing the recording head, the suction device being driven by the driving device after the wiping device and the capping device have been driven. With this feature, the suction device is also rotatable bidirectionally. In particular, when the tube pump is used, it is possible to release the pulley from the tube. It is prevented that the pulley is left pressing the tube, without using any special mechanism. The recording head may be capped without driving the pump. Therefore, there is no fear that the pump tube is pressed at the time of opening and closing the cap.
4) In the head jetting property maintenance device 2) or 3), the partially toothless gear is formed of a gear train including four partially toothless gears, which are in mesh with a wiper gear for driving the wiping device, a cap gear for driving the capping device, and the planet gears, respectively. With this feature, the rotations of the planet gears, respectively, may be transmitted to the wiper gear and the cap gear reliably. As a result, a positioning accuracy of the cap and the wiper may be improved, and the capping device and the wiping device may be operated independently.
5) In the head jetting property maintenance device 4) above, the wiper gear includes a lever and a cam mechanism for horizontally moving the wiping device to the recording head, and the cap gear includes a cam mechanism for vertically moving the capping device with respect to the recording head. With this feature, the invention may be applied to the conventional wiping device and the capping device, each having the lever and the cam mechanism. Accordingly, troublesome design work, such as design modification, may be simplified.
6) To accomplish the object of the invention, there is provided a head jetting property maintenance device for maintaining an ink jetting property of a recording head for jetting ink droplets to a recording medium, the head jetting property maintenance device having a wiping device for wiping the recording head, a capping device for sealing the recording head, and a driving device for positioning the wiping device and the capping device at predetermined positions, wherein a guiding/fixing device for guiding, at the time of positioning of the wiping device, the positioning operation of the wiping device, and for positioning and fixing the wiping device; and a guiding/fixing device for guiding, at the time of positioning of the capping device, the positioning operation of the capping device, and for positioning and fixing the capping device.
With this feature, the wiping device and the capping device maybe held at a fixed position. Therefore, if the user touches the wiping device and the capping device, there is no chance that the wiping device and the capping device are displaced. Accordingly, there is no need for the work to return the wiping device and the capping device to predetermined positions. Further, there is no chance that parts forming the wiping device and the capping device collide with each other. In this respect, the maintenance work is easy. The wiping device and the capping device are always positioned highly accurately. Further, there is no need of making the phase adjustment of the parts forming the wiping device and the capping device in assembling the head jetting property maintenance device. Accordingly, the cost to manufacture the head jetting property maintenance device is reduced.
7) In the head jetting property maintenance device 6) above, when the wiping device wipes the recording head, the driving device turns the wiping device upward, while moving downward and positioning the capping device, and when the capping device seals the recording head and sucks ink from the recording head, the driving device turns downward the wiping device, while moving upward and positioning the wiping device.
With this feature, when the wiping device is operated in place of the capping device, only the wiping device is rotated, and there is no need of rotating the capping device. Therefore, the head jetting property maintenance device may be constructed in a simple mechanism. Accordingly, the cost of manufacturing the head jetting property maintenance device is reduced.
8) The head jetting property maintenance device 6) or 7) above further comprises a suction device for sucking inside the cap of the capping device, and wherein aid driving device drives the suction device. With this feature, the wiping device, the capping device and the suction device may be operated by a single driving device. Thus, the capping device and the suction device may be operated by a single driving device. As a result, the head jetting property maintenance device per se may be reduced in size.
9) In any of the head jetting property maintenance devices 6) to 8), the driving device drives the respective devices independently. With this, the load imposed on the driving device is reduced. Therefore, the power consumption by the ink jet printer is reduced.
10) In any of the head jetting property maintenance devices 6) to 9) above, the wiping device and the capping device are able to return to their initial positions from any positions without use of sensing devices. With this feature, even when the plug is mistakenly pulled out of the electrical outlet or unexpected power failure occurs, and the head jetting property maintenance device stops its operation, it may be reset from its state.
11) In any of the head jetting property maintenance devices 6) to 10), a driving side and a driven side of the wiping device in the driving device are provided with partially toothless gears, respectively. A driving device, which is capable of solely driving the wiping device, the capping device and the suction device, can be realized with a simple structure.
12) In any of the head jetting property maintenance devices 7) to 11), the wiping device is rotatably mounted on the capping device. Therefore, the device for vertically moving the capping device and the device for rotating the wiping device may easily be constructed with the same mechanism. This feature makes the head jetting property maintenance device compact.
13) In any of the head jetting property maintenance devices 7) to 12), the wiping device includes a rotatable wiper for wiping the recording head, and a wiper cleaner for wiping out materials sticking onto the wiper in a manner that the wiper cleaner rubs with the wiper when the wiper rotates. Therefore, the wiper may be constructed to be maintenance free, so that the maintenance of the head jetting property maintenance device is easy.
14) In any of the head jetting property maintenance devices 7) to 13), the driving device includes a cam provided with a gear for transmitting a drive force for the wiping device, and transmitting a drive force for moving the capping device vertically. Therefore, the device for vertically moving the capping device and the device for rotating the wiping device may be constructed using simple mechanical parts. This results in improvement of the positioning accuracy of those devices, and reduction of maintenance and manufacturing cost.
15) In the head jetting property maintenance device 14), the driving device includes a normal rotation gear for normal rotation and a reverse rotation gear for reverse rotation, which alternately come into engagement with a came with the partially toothless gear. This feature enables the normal rotation gear and the reverse rotation gear rotation to be separately constructed. As a result, a more reliable positioning and fixing is ensured when the wiping device is used and when the capping device is used.
16) To accomplish the object of the invention, there is provided a head jetting property maintenance device for maintaining an ink jetting property of a recording head for jetting ink droplets to a recording medium, the head jetting property maintenance device having a wiping device for wiping the recording head; a capping device for sealing the recording head; and a driving device operating such that when the wiping device wipes the recording head, the driving device turns the wiping device upward and moves downward and positions the capping device, and when the capping device seals the recording head to suck ink therefrom, the driving device turns downward the wiping device and moves upward and positions the capping device. The head jetting property maintenance device thus constructed is improved such that the driving device includes a friction clutch mechanism transmits a drive force when the wiping device is driven to start its turn, and releases the drive force when the wiping device is stopped in turn.
Accordingly, there is no need of rotating the capping device, and therefore of providing a space allowing the device to rotate around the device. The result is to realize the size reduction of the ink jet printer into which the head jetting property maintenance device is incorporated, and maintain the position precision of the capping device and the recording head in high level. After the wiping device is rotated upward or downward, the friction clutch mechanism may be made to run idle. Therefore, the wiping device may always be positioned at a fixed position. Accordingly, the initializing and assembling of the wiping device are easy.
17) The head jetting property maintenance device 16) above further comprising a suction device for sucking inside the cap of the capping device, and wherein aid driving device drives the suction device. With provision of the suction device, ink droplets sticking to the nozzles of the recording head may be sucked, so that it is possible to maintain the print accuracy in high level.
18) In the head jetting property maintenance device 16) or 17), a gear drive mechanism using a partially toothless gear is used for an intermediate power transmission mechanism of the friction clutch mechanism. Accordingly, the friction clutch mechanism, which may be driven even if a load in excess of a friction force is imparted to the intermediate power transmission mechanism, is realized with a simple structure.
19) In any of the head jetting property maintenance devices 16) to 18), the wiping device and the capping device are able to return to their initial positions from any positions without use of sensing devices. With this feature, even when the plug is mistakenly pulled out of the electrical outlet or unexpected power failure occurs, and the head jetting property maintenance device stops its operation, it may be reset from its state.
20) In any of the head jetting property maintenance devices 16) to 18), the friction clutch mechanism includes two drive force transmission devices, and a pressing device for pressing the drive force transmission devices with each other, and the drive force transmission devices are integrally coupled to the wiping device. With this, a friction force is generated between the two drive forces transmission devices, thereby forming a friction clutch mechanism.
21) In any of the head jetting property maintenance device 20), the pressing means is a compression gear for pressing the normal gear against the partially toothless gear and vice versa. Therefore, the friction clutch mechanism may be constructed in a simple mechanism. The cost to manufacture the head jetting property maintenance device may be reduced.
22) In any of the head jetting property maintenance devices 16) to 21), the wiping device is rotatably mounted on the capping device. Therefore, the device for vertically moving the capping device and the device for rotating the wiping device may easily be constructed with the same mechanism. This feature makes the head jetting property maintenance device compact.
23) In any of the head jetting property maintenance device 16) to 22), the driving device includes a cam having a partially toothless gear which transmits, a drive force during the rotation of the wiping device through the two drive force transmission devices, and transmits a drive force when the capping device vertically moves. Therefore, the device for vertically moving the capping device and the device for rotating the wiping device may be constructed using simple mechanical parts. This results in improvement of the positioning accuracy of those devices, and reduction of maintenance and manufacturing cost.
24) According to an additional aspect of the invention, there is provided an ink jet printer having a recording head for jetting ink droplets to a recording medium, which the printer being characterized by a head jetting property maintenance device defined in any of the head jetting property maintenance devices 1) to 23). Accordingly, the ink jet printer having the operation and effects as mentioned above is provided.